Eggshell membrane separation method

ABSTRACT

A method for processing unseparated egg shells is provided. The method includes placing the unseparated egg shells in a fluid tank containing a fluid mixture, applying cavitation to the fluid mixture to thereby assist in separating the egg shell membranes from the egg shells, and recovering the egg shell membranes. Preferably, the fluid mixture is recirculated to thereby provide for continuous processing of unseparated egg shells. The method may further include drying the egg shell membranes to produce dried egg shell membranes which may then be vacuum packaged for storage and/or transport. The dried egg shell membranes may then be subjected to an extraction process for extracting at least one type of polypeptide from the egg shell membranes. Collagen, hyaluronic acid, or amino acids of interest may be extracted from the egg shell membrane and purified for numerous uses.

RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent ApplicationNo. 60/644,643, filed Jan. 18, 2005, incorporated by reference herein inits entirety.

BACKGROUND OF THE INVENTION

The present invention relates to methods, apparatus, and a system foreggshell membrane separation and a purified form of egg shell membranesproduced by the separation method. The present invention addresses anumber of different problems, some of which may seem unrelated withouthaving the benefit of this disclosure. The problems include, but are notlimited to, the costs associated with landfill disposal of egg shellmembranes, the need for elemental calcium for various uses, and the needfor collagen and other materials naturally present in egg shellmembranes. Some of these problems are discussed in U.S. Pub No.2003/0209617A1 to MacNeil, U.S. Pat. No. 6,649,203B1 to Thoroski, U.S.Pub No. 2004/0166213A1 to Thoroski, and U.S. Pat. No. 6,790,454B1 toAbdul Malak et al, all of which are incorporated by reference herein,each in its entirety.

In the U.S., there has been increased consumption of eggs during the1990s. In 1997, over 5,000 tons of eggshell membranes have beenavailable on the U.S. market. A related problem to the processingnecessary to support this magnitude of egg processing is the cost forlandfill disposal of eggshell membranes. This waste material createdadditional problems as it is further observed that this type of hatcherywaste material is considered to be odiferous.

Eggshell powder is used in the food industry, including animal and humannutritional supplements. Eggshells provide approximately 36-37 percentelemental calcium in addition to traces of phosphorous and other traceelements. Thus, for example, 500 mg of dried powdered eggshell providesapproximately 180 mg elemental calcium. This compared vary favorably toother calcium salts. For example, calcium carbonate provides 40 percentelemental calcium, calcium citrate provides 21 percent elementalcalcium, calcium lactate provides 13 percent elemental calcium, calciumgluconate provides 9 percent elemental calcium, dicalcium phosphateprovides 23 percent elemental calcium (and 19 percent phosphorus), andbone meal provides 20 percent elemental calcium (and 17 percentphosphorus). A single large eggshell has a mass of approximately 6 g andprovides approximately 2200 mg of calcium.

In addition to potential uses of the egg shell, the egg shell membraneis known for being rich in a number of different materials, including,without limitation collagen, hyaluronic acid, lysine, histidine,arginine, threonine, glutamic acid, proline, glysine, cysteine, valine,methionine, isoleucine, leucine, tyrosine, phenylalanine and tryptophan.Some of these materials are well known as high value materials, yet dueto various problems, these materials go to waste. For example, considerthat approximately 10 percent of an eggshell membrane is collagen typeI, V, and X. Over 300 tons of collagen is theoretically available.Collagen has a number of biomedical uses, wound dressing, including inskin grafts, tissue replacement products, plastic surgery, angioplastysleeves, cornea repair, cornea implants, prosthetic implants, and otherapplications. Collagen is also used in the cosmetic industry.

Collagen constitutes about 20 to 30 percent of the total body protein invertebrates. It is a fibrous protein and functions primarily as asupporting tissue and scaffolding for other proteins and cells. It ispresent throughout the body but exists in high concentrations in skin,tendon, and bone. Collagen is recovered from these tissues by a varietyof techniques the oldest known method being the boiling of the tissue inwater which denatures some of the collagen and forms the well-knowngelatin upon cooling. For use as a biomaterial, however, collagen mustbe recovered in native, undenatured form, with little or no destructionof the basic rigid triple helical structure (tropocollagen).

Undenatured native collagen is recovered principally by two methods. Thefirst method is in solution by dissolving the collagen in acids, bases,salts, or by enzyme digestion in which case the collage becomes actuallydissolved. The second method involves extraction in solid, undissolved,fiber form usually by the action of aqueous salt on minced, comminutedcollagen raw material to produce a dispersion from which the solid isrecovered by centrifuge.

Hyaluronic acid is another example of a high value material which isnaturally present in and a constituent of egg shell membranes. U.S. Pat.No. 6,946,551 to Long et al. generally discloses deriving hyaluronicacid from eggshell membranes. Hyaluronic acid can be used in variousapplications including cosmetics, eye drops, nutraceuticals, and variousother medical applications.

Thus, it is clear that it would be highly advantageous if collagen,hyaluronic acid or other materials could be commercially extracted fromegg shell membranes. Despite the general recognition of the tremendouspotential value of egg shell membranes when its constituents areextracted, little has been done to realize this value. Thus hatcherywaste continues to included unseparated egg shells which is still beingsent to land fills. The present inventor has recognized and discoverednumerous problems that prevent the use of egg shell membranes. Includingproblems which prevent hatcheries from separating egg shell membranes ina useable form. The present invention has also recognized specificproblems in the context commercial context which provide additionalchallenges not present in a laboratory environment and heretoforeunappreciated.

One of the problems relates to environmental and sanitary conditionsassociated with a hatchery. Present day production processes were notdesigned with the idea of separating egg shell membranes from egg shellsand then extracting egg shell membranes. Present day hatcheries arelikely to have bacteria in sufficient amounts to contaminate eggshellmembranes during the process of separation.

Another problem relates to the need for a production process for eggshell membrane separation which is continuous. In the hatcheryenvironment, hatchery waste is being continuously produced, andtherefore it would be highly desirable for egg shell membranes to beseparated from egg shells continuously as well. To not do so, wouldcreate significant problems in that either hatchery operation would beslowed, not all hatchery waste would be processed, hatchery waste wouldneed to be processed when other hatchery operations were offline, orsimilar problems which would be unacceptable in the hatcheryenvironment.

Therefore it is a primary object, feature, or advantage of the presentinvention to improve upon the state of the art.

It is a further object, feature, or advantage of the present inventionto reduce waste used in egg processing.

Another object, feature, or advantage of the present invention is toproduce egg shell powder from what would otherwise be egg processingwaste material.

Yet another object, feature, or advantage of the present invention is toproduce high value produces such as collagen, hyaluronic acid, or othertypes of polypeptides from what would otherwise be egg processing wastematerial.

A still further object of the present invention is to produce newrevenue streams for hatcheries and egg producers.

Yet a further object, feature, or advantage of the present invention isto provide a method for separating egg shell membranes from egg shells.

A still further object, feature, or advantage of the present inventionis to provide a method that reduces pathogens and contaminants inpowderized egg shells and eggshell membranes.

Another object, feature, or advantage of the present invention is toprovide for reducing odor associated with egg processing and egg waste.

A further object, feature, or advantage of the present invention is toprovide for continuous processing of egg shells.

Another object, feature, or advantage of the present invention is toprovide for automated processing of egg shells.

Yet another object, feature, or advantage of the present invention is toprovide for methods, apparatus, and systems for processing egg shellsthat are scaleable.

A further object, feature, or advantage of the present invention is toprovide for methods, apparatus, and systems for processing egg shellsthat are cost effective.

A yet further object, feature, or advantage of the present invention isto provide for a systems for processing egg shells that is portable.

A still further object, feature, or advantage of the present inventionis to provide for methods, apparatus, and systems for processing eggshells that does not damage collagen, hyaluronic acid or other materialsto be extracted.

A still further object, feature, or advantage of the present inventionis to provide for a method of processing egg shells which allowsextraction processes to be performed on egg shell membranes at locationsremote from egg hatcheries.

One or more of these and/or other objects, features, and advantages ofthe present invention will become apparent from the specification andclaims that follow.

BRIEF SUMMARY OF THE INVENTION

According to one aspect of the present invention, a method forprocessing unseparated egg shells is provided. The method includesseparating egg shell membranes from the egg shells, drying the egg shellmembranes, and processing the egg shell membranes after drying toextract at least one type of polypeptide from the egg shell membranes.The step of separating can include placing the unseparated egg shells ina fluid tank containing a fluid mixture, applying cavitation to therebyseparate the egg shell membranes from the egg shells, recovering the eggshell membranes, and recovering the egg shells. Preferably, the step ofseparating egg shell membranes from the egg shells is performed byequipment which provides for continuous processing of unseparated eggshells. The process also preferably includes recirculating the fluidmixture.

The drying process preferably includes drying the egg shell membranes toa moisture content of between 3 percent and 10 percent by weight. Thestep of drying is performed at a temperature which preserves the atleast one polypeptide. For example, where the type of polypeptides toextract is collagen, the temperature should be less than the meltingtemperature for collagen, and preferably less than about 40 degreesCelsius. Preferably the drying is infrared drying.

After drying the egg shell membranes may be vacuum packaged tofacilitate storage or transport of the egg shell membranes for laterextraction processing. The egg shell membranes can be further processedat a location remote from the location where the separation processoccurs. During extraction, the polypeptide extracted may be an aminoacid such as lysine, histidine, arginine, threonine, glutamic acid,proline, glysine, cysteine, valine, methionine, isoleucine, leucine,tyrosine, phenylalanine, or tryptophan. The polypeptide may be aprotein, may be collagen, hyaluronic acid, or other material of highvalue.

According to another aspect of the present invention, a method forprocessing unseparated egg shells is provided. The method includesplacing the unseparated egg shells in a fluid tank containing a fluidmixture, such as a mixture of distilled water and acetic acid, applyingcavitation to thereby assist in separating the egg shell membranes fromthe egg shells, recovering the egg shell membranes, and recirculatingthe mixture of distilled water and acetic acid to thereby provide forcontinuous processing of unseparated egg shells. The method may furtherinclude recovering the egg shells and grinding the egg shells to produceegg shell powder. Also, the method may further include drying the eggshell membranes to produce dried egg shell membranes which may then bevacuum packaged for storage and/or transport. The dried egg shellmembranes may then be subjected to an extraction process for extractingat least one type of polypeptide from the egg shell membranes. Collagen,hyaluronic acid, or amino acids of interest may be extracted from theegg shell membrane and purified for numerous uses.

According to another aspect of the present invention, a system forprocessing unseparated egg shells is provided. The system includes afluid container containing a fluid mixture, the fluid container havingan inlet and an outlet. The system also includes a mixer adapted forapplying cavitation to the fluid mixture to thereby assist in separatingegg shells from egg shell membranes and to move the fluid mixture fromthe inlet to the outlet. There is at least one sieve positionedproximate the outlet to further assist in separating the egg shells fromthe egg shell membranes. There is also a means for recovering the fluidmixture at the outlet and providing the fluid mixture to the inlet tothereby provide for continuous processing of unseparated egg shells.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram which provides an overview of one embodimentof the system of the present invention.

FIG. 2 is a perspective view illustrating one embodiment of an egg shellmembrane separation component which provides for continuous processing.

FIG. 3 is a perspective view illustrating internal structure within theegg shell membrane separation component shown in FIG. 2.

FIG. 4 is a front view of another embodiment of an egg shell membraneseparation component which provides for continuous processing.

FIG. 5 is a perspective view of the egg shell membrane separationcomponent shown in FIG. 4.

FIG. 6 is a front view of another embodiment of an egg shell membraneseparation component.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention provides for separation of eggshell membranes fromegg shells in a manner which provides for significant advantages andbenefits. In particular, but without limitation, the present inventionprovides for separation of eggshell membranes from egg shells in amanner which allows for continuous processing such that the separationcan occur at a hatchery, in a manner which reduces pathogens in theeggshell membranes, in a manner which prevents damage to high valuematerials within the egg shell membranes (such as, but not limited tocollagen or hyaluronic acid), and in a manner which provides forpreserving the egg shell membranes for storage or transport.

FIG. 1 is a block diagram which provides an overview of one embodimentof the system 10 of the present invention. As shown in FIG. 1, hatcherywaste 12 is received. The hatchery waste 12 consists of unseparated eggshells and egg shell membranes that remain after the cracking process.Although the term “unseparated” is used, it is to be understood thatthere may be some degree of separation at this point. This hatcherywaste 12 is received at an egg shell membrane separation component 14.The present invention contemplates numerous embodiments for the eggshell membrane separation component, and preferred embodiments will bedescribed in greater detail later herein. It is preferred that the eggshell membrane separation component 14 provide for continuous processingof hatchery waste 12. The egg shell membrane separation component 14outputs egg shell membranes 18 and egg shells 16 each type of resultingproduct may then be separately processed. The egg shells 16 are conveyedto a grinding component 20 in order to produce eggshell powder 22. Theegg shell powder can be used in numerous ways, including in animalnutrition, as a human nutritional supplement, or otherwise.

The eggshell membranes 18 are then received at a drying component 24.The drying component 24 preferably provides for infrared drying. Afterdrying, the egg shell membranes are conveyed to an extraction component26. The egg shell membranes are preferably conveyed to a vacuumpackaging component 34 to package the egg shell membranes in a bag orotherwise in order to preserve the egg shell membranes for storage ortransporting 32.

The extraction component 26 provides for extracting one or morematerials from the eggshell membranes. Although various types ofpolypeptides may be extracted, of particular interest is collagen 28,and various amino acids 30, including hyaluronic acid (HA) 30. Suchmaterials are high value materials which are difficult and/or expensiveto obtain from other sources.

FIG. 2 is a perspective view illustrating one embodiment of an egg shellmembrane separation component 100 which provides for continuousprocessing. The system 100 includes a main tank 102 for containing afluid mixture of distilled water received from the distilled water tank106 and acetic acid received from the acetic acid tank 108. Although thepresent invention contemplates that different ratios of water and aceticacid can be used, one such ratio is approximately 1 part water(preferably distilled water) and 1 part 5 percent acetic acid. Such asolution comprises approximately 2.5 percent acetic acid. The use ofacetic acid or vinegar assists in eliminating odors as well as killingpathogens such as bacteria and viruses.

An insertion cone 104 or funnel is shown for receiving unseparated eggshells. In this particular embodiment, the unseparated egg shells areplaced within mesh containers, such as, but not limited to mesh bags. Inother embodiments, mesh containers need not be used. The mesh containersare then inserted into the insertion cone 104. Within the main tank 102is a mixer 116 which is best shown in FIG. 3. The mixer 116 can be asubmersible mixer which is commercially available from Flygt, but may beof other type or design. Preferably there is a protective mesh screen118 to protect the mixer 116 as shown in FIG. 3. The mixer 116 producesfluid flow to assist in separating the eggshell membranes from the eggshells. The movement of the fluid turns an outer auger 120 and drivesthe mesh bags through the tank 102. An inner auger 122 is used drive theegg shells through the tank 102.

The structure of the outer auger 120 and the inner auger 122 is bestshown in FIG. 3. There is an inner mesh sleeve 124 around the innerauger 122 to protect the mesh bags from the inner auger 122. The innermesh sleeve 124 is also best shown in FIG. 3. Friction forces assist inseparating the egg shell membranes from the egg shells. As shown in FIG.2, a calcium outlet 112 is shown on the opposite end of main tank forcollecting the egg shells. A mesh bag outlet 114 is shown for collectingthe mesh bags containing egg shell membranes. Fluid from the separationprocess is recycled. A fluid recycle tank 110 is shown. Note that theembodiment shown in FIG. 2 allows for continuous egg shell separationprocessing which is highly desirable in the environment of a hatcherywhere a continuous process produces hatchery waste in the form ofunseparated egg shells.

FIG. 4 is a front view of another embodiment of an egg shell membraneseparation component which provides for continuous processing. Thisembodiment may sometimes be referred to as a U-turn embodiment. In theegg shell membrane separation component 200 of FIG. 4, a funnel 202 isshown for receiving unseparated egg shells. Note that in thisembodiment, no mesh containers need be used, instead the unseparated eggshells are placed directly in the funnel 202. The funnel leads to aninlet for a conduit or pipe 204. The pipe 204 may be composed of aplastic material such as polyvinyl chloride (PVC). The pipe 204 isgenerally shaped to include a U-turn. Within the pipe 204 is a mixer206, such as a submersible mixer commercially available from Flygt. Themixer provides for cavitation within the pipe to drive fluid andeggshells through the pipe and thereby assist in the separation process.A support structure 208 is shown for supporting the pipe 204. Inaddition, a pipe separator 210, first sieve 212, and second sieve 214are shown. The pipe separator 210, first sieve 212, and second sieve 214assist in collecting the egg shells separately from the egg shellmembranes. The egg shell membranes are separated onto a conveyor 216while the egg shells are separated onto a conveyor 218.

FIG. 5 is a perspective view of the egg shell membrane separationcomponent 200 showing the outlet of the pipe 204. The pipe separator 210assists in separately recovering the egg shell membranes and the eggshells, after the cavitation action within the pipe 204 has separatedthe egg shells from the egg shell membranes. A first mesh sieve 212 isshown for collecting the egg shell membranes which are larger than theegg shells. A second mesh sieve 214 is shown for collecting the eggshells. Note that the fluid used in the egg shell membrane separationcomponent 200 is recycled at the outlet of the pipe 204 and back intothe inlet of the pipe 204. The egg shell membrane separation component200 provides for continuous processing of unseparated egg shells intoegg shells and egg shell membranes.

FIG. 6 is a front view of another embodiment of an egg shell membraneseparation component 300. The system 300 includes a first tank 302 and asecond tank 304, with the first tank 302 positioned above the secondtank 304, the tanks being supported by a support structure 306. Thetanks 302, 304 contain a fluid comprising distilled water and aceticacid. A mixer 308 is positioned within the first tank 302 for providingcavitation to assist in separating the egg shells from the egg shellmembranes. A membrane sieve 316 is placed within the first tank 302 forcollecting egg shell membranes. A valve 312 is positioned at the bottomof the first tank. When the valve 312 is opened, fluid containing theegg shells passes through a mesh pipe filter such that the egg shellsare recovered. The fluid from the first tank drains into the second tankwhere it is filtered and pumped by fluid filter/pump 314 through thefluid recirculation pipe 310 back into the first tank 302.

Returning to FIG. 1, a drying component 24 is shown. The presentinvention has identified four factors of particular importance to beconsidered in the drying process. These factors are temperature,moisture, speed, and size of particles. With respect to temperature, thedrying component 24 should provide for drying the egg shell membrane ina manner that does not damage material which is to be later extracted.For example, where the material to be extracted is collagen, the dryingmust be at a temperature lower than the melting point of collagen, suchas less than 50 degrees Celsious, and preferably less than about 40degrees Celsuis. For extraction of collagen, the present inventor hasdetermined that a range of about 3 percent to 10 percent moisture (orany value within in this range) as the moisture level for the eggshellmembrane is preferred. With respect to speed, the faster the dryingprocess the less contamination. Wet egg shell membranes are highlyproblematic as they are a virtual breeding ground for pathogens such asharmful bacteria, including phytophagous bacteria (bacteria which eatsplant tissue). Therefore, it is advantageous to dry the egg shellmembranes quickly with quick evaporation. With respect to size ofparticles, the present inventor has found a preferred range for the sizeof particles to be bigger than about 3-4 mm in size, preferably in therange of about 4 mm to about 7 mm.

The present inventor has tested various types of drying components,including infrared drying, spray drying, conductive heating, and freezedrying and has found infrared heating to be preferable. Examples ofinfrared heating component which can be used include those which arecommercially available from MCD Technologies of Tacoma, Wash., USA. Thepresent invention further contemplates that the infrared heating can becombined with conductive heating to thereby further decrease the amountof heating time. Infrared heating is preferred over spray drying as withspray drying, increased bacteria levels have been observed. Infraredheating is preferred over freeze drying as freeze drying is generallyimpracticable in the context of a hatchery environment. In addition, thecost of freeze drying can be high.

In another embodiment, the drying component uses the REFRACTANCE WINDOWdrying technology of MCD Technologies which incorporates infraredheating. In this process, the wet egg shell membranes are placed on thetop surface of a continuous sheet of special plastic. The conveyor beltfloats upon a surface of hot water. Infrared energy in the circulatingwater beneath the belt passes directly into the moist product. Thisrapidly dries it at atmospheric pressure rather than under a vacuum.Such a drying component is further described in U.S. Pat. No. 6,047,484to Bolland, et al., hereby incorporated by reference in its entirety.Where a conveyor belt is used, it is preferred that the wet membranesare taken in a single layer format to thereby promote quick drying.

Returning to FIG. 1, a vacuum packaging component 34 is shown. Thepresent invention provides for vacuum packaging dried egg shellmembranes for storage or transport off site to a location remote fromthe hatchery. Numerous types of commercially available vacuum packagingsystems can be used. Such a system is used to package the egg shellmembranes in vacuum sealed plastic bags or other containers. Of course,the present invention is not limited to the particular type of vacuumpacking system used.

Although specific embodiments of the present invention are providedherein, the present invention is not to be limited to these embodiments.The present invention contemplates numerous variations in the specificmethodology used and the specific structures used. One skilled in theart having the benefit of this disclosure will understand that numerousvariations and substitutions are within the spirit and scope of theinvention.

1. A method for processing unseparated egg shells, comprising: placingunseparated egg shells in a fluid tank containing a fluid mixture;separating egg shell membranes from the egg shells by applyingcavitation to the fluid mixture to thereby separate egg shell membranesfrom the egg shells; recovering the egg shell membranes; drying the eggshell membranes; processing the egg shell membranes after drying toextract at least one type of polypeptide from the egg shell membranes.2. The method of claim 1 further comprising recovering the egg shells.3. The method of claim 1 wherein the step of separating egg shellmembranes from the egg shells being performed by equipment providing forcontinuous processing of unseparated egg shells.
 4. The method of claim3 wherein the step of separating egg shell membranes from the egg shellsfurther comprises recirculating the mixture.
 5. The method of claim 1wherein the step of drying is drying the egg shell membranes to amoisture content of less than 10 percent by weight.
 6. The method ofclaim 1 wherein the step of drying is drying the egg shell membrane to amoisture content of less than 7 percent by weight.
 7. The method ofclaim 1 wherein the step of drying is drying the egg shell membrane to amoisture content between 3 percent and 10 percent by weight.
 8. Themethod of claim 1 wherein the step of drying being drying at atemperature which preserves the at least one polypeptide.
 9. The methodof claim 8 wherein the temperature is less than a melting temperatureassociated with the at least one polypeptide.
 10. The method of claim 8wherein the at least one type of polypeptide is collagen and thetemperature is less than about 40 degrees Celsius.
 11. The method ofclaim 1 wherein the drying is infrared drying.
 12. The method of claim 1further comprising vacuum packaging the egg shell membranes after dryingto facilitate storage of the egg shell membranes before processing. 13.The method of claim 12 further comprising transporting the egg shellmembranes after vacuum packaging to a location remote from a locationwhere the step of separating egg shell membranes occurs.
 14. The methodof claim 1 further comprising obtaining the unseparated egg shells fromhatchery waste.
 15. The method of claim 14 wherein the at least onepolypeptide is comprised of amino acids from the set of lysine,histidine, arginine, threonine, glutamic acid, proline, glysine,cysteine, valine, methionine, isoleucine, leucine, tyrosine,phenylalanine and tryptophan.
 16. The method of claim 1 wherein the atleast one polypeptide is a protein.
 17. The method of claim 1 whereinthe at least one polypeptide comprises collagen.
 18. The method of claim1 wherein the at least on polypeptide is hyaluronic acid.
 19. The methodof claim 1 wherein the step of separating egg shell membranes from theegg shells being performed by equipment providing for continuousprocessing of unseparated egg shells.
 20. A method for processingunseparated egg shells, comprising: placing the unseparated egg shellsin a fluid tank containing a fluid mixture; applying cavitation to thefluid mixture to thereby assist in separating the egg shell membranesfrom the egg shells; recovering the egg shell membranes; recirculatingthe fluid mixture to thereby provide for continuous processing ofunseparated egg shells.
 21. The method of claim 20 further comprisingrecovering the egg shells.
 22. The method of claim 21 further comprisinggrinding the egg shells.
 23. The method of claim 20 further comprisingdrying the egg shell membranes to produce dried egg shell membranes. 24.The method of claim 23 further comprising vacuum packaging the dried eggshell membranes for storage or transport.
 25. The method of claim 20further comprising extracting at least one type of polypeptide from theegg shell membranes.
 26. The method of claim 20 further comprisingextracting collagen from the egg shell membranes.